Metal-bending machine with holddown means to prevent die deflection



Aug. 10, 1948. B. GREEN METAL BENDING MACHINE WITH HOLD-DOWN MEANS TOPREVENT DIE DEFLECTION Filed June 21, 1945 2 Sheets-Sheet 1 INVENTOR.L55 5. GEE/V I Era- 1422;

Aug. 10, 1948. B. GREEN 2,446,324

METAL BENDING MACHINE WITH HOLD-DOWN MEANS TO PREVENT DIE DEFLECTION 2Sheets-Sheet 2 Filed 'June 21 1945 INVENTOR L55 8. GEN

flrroE/MYJ Patented Aug. 10, 1948 METAL-BENDING MACHINE WITH HOLD- DOWNMEANS TO PREVENT DIE DEFLEO- TION Lee B. Green, Lakewood, OhioApplication June 21, 1945, Serial No. 600,765

11 Claims. (01. 153-33) This invention relates to metal working machinesand, more particularly, to a machine for carrying out forming andbending operations and which is an improvement over the machinedisclosed in my earlier Patent No. 2,287,933 granted June 30, 1942.

As one of its objects, the present invention provides a forming andbending machine generally similar to that of my earlier patent but whichis more compact and embodies several improvement features which enableit to carry out the intended operations in a more accurate andsatisfactory manner.

Another obi ect of this invention is to provide an improved machine ofthis character, in which novel hold-down means is employed for renderingthe operations more accurate and satisfactory by substantiallyeliminating the effects of deflection in the machine and accumulatedlost motion between the various moving parts of the machine.

A further object of the invention is to provide an improved machine ofthe character mentioned, having a pivoted carriage for the movableclamping and forming die and wherein novel holding means for thecarriage protects the pivot mounting thereof from harmful stresses.

Still another object is to provide an improved machine of thischaracter, in which a thrust absorbing backing is employed for thestationary die mount for preventing shifting or deflectionthereof.

shown in said earlier patent but which embodies important improvementfeatures which will be described hereinafter. The improved machine isprovided with an elongated generally horizontally extending rigid hollowframe ll having thereon a stationary die mount I! which is connectedwith the frame at a point intermediate its ends and extends asubstantial distance thereabove. The mount l2 forms a support for one ofthe main dies of the machine, in this instance. the female die l3. Onone side of the die mount [2 the frame II is provided with spaced waysIla forming a guideway I4 on which a slide [5 is reciprocably movabletoward and away from the mount ii.

A second main die, in this instance, a male die I6, is carried by theslide l5 and movable thereby into and out of working cooperation withthe female die [3. The male die I6 is not carried directly by the slideIE but by a carriage H which is mounted on the slide for swingingaboutthe axis of an upright pivot post I8 carried by the slide.

The carriage I1 is shown in the drawings in full lines in its workingposition in which it is disposed in substantial alignment with the pathof reciprocating movement of the slide I5 but is adapted to be' swunglaterally to the broken line position of Fig. 2 in which the carriageextends in angular relation to such path of reciprocating This inventionalso provides for a more posi- 4 tive and direct actuation of thebending dies by the use of pivoted individual power cylinders forswinging the wings which carry the bending dies.

The invention can be further briefly summarized as consisting in certainnovel combinations and arrangements of parts hereinafter described andparticularly set out in the claims hereof.

In the accompanying sheets of drawings,

Fig. 1 is a perspective view showing a metal working machine embodyingthe improvement movement so as to facilitate the removal of a work piecefrom the male die IS. The swinging of the carriage can be effected bymeans of a hydraulic power cylinder 19 fixed thereon and whose pistonrod 20 carries a rack 2| which cooperates with a gear 22 fixedly mountedon the pivot post l8 of the slide l5.

The female die l3 may be of any desired shape or contour, depending uponthe operation to be performed thereby and in this instance is asubstantially quadrangular member having a shallow concave contour inits front or working face similar to the female die shown in saidearlier patent and serves as a combined forming and clamping die for thework piece. The male die l6 likewise may be of any desired shape orcontour and in this instance is of a convexly rounded contour andcooperates with the female die l3 for the accomplishment of a combinedforming and clamping operation. The sides of the male die form roundedanvil portions I6a with which the bending dies cooperate as explainedhereinafter.

The metal working machine "I can be used for various purposes, forexample, it can be used in carrying out a simple forming or stampingoperation on sheet metal work pieces,. or it who used for variousbending operations to be performed on plain or flanged sheet metal workpieces or structural forms while the latter are clampingly held by themain dies i3 and II. or it can be used for carrying out a combinedforming and bending operation. The particular, dies l8 and 7 ll shown inthis instance are intended for such a combined forming and bendingoperation and can be used for producing refrigerator cabinets or thelike from flanged sheet metal work pieces as illustrated and describedin said earlier P tent.

The bending operation performed by the machine ll is carried out by theuse of a pair of bending dies 24 in cooperation with the main dies i8and It. The bending dies 24 are substantially identical with the bendingdies disclosed in said earlier patent and are plate-like members mountedfor similar rocking movement. The bending dies 24 cooperate with and arerockable around the above mentioned anvil portions Ila of the male dieit when the latter is in its closed position. These bending dies arecarried by pivotally mounted wings 2B which swing about pivot axes 28for causing such rocking of the bending dies around the anvil portions awhile the work piece is being clampingly held against the female diellbythe male die ll.

During such rocking of the bending dies 24 pressure is applied to thebacks thereof by the spring pressed rollers 21 of the wings 25 andslippage of the bending dies relative to the anvil portions its isprevented by the racks 28 of the bending dies meshing with the fixedgears 29. During this bending operation, laterally extending portions ofthe work piece are bent around the anvil portions lea of the male die tothereby shape the work piece to the desired form such as thesubstantially U-shaped refrigerator cabinet shown in said earlierpatent.

As thus far described. the machine II is substantially the same as theforming and bending machine disclosed in said earlier patent. Theimprovement features embodied in the present machine render the samemore compact and provide for a more accurate and satisfactoryperformance of the forming and bending operations. These improvementfeatures will be described next.

One of these improvement features provides for a more direct actuationof the slide II by the use of a hydraulic power cylinder 3i which islocated in the hollow frame I I and is fixed thereto. This powercylinder is provided with a reciprocable piston and a piston rod 23which projects from the cylinder and has its outer end attached to theslide I 5 as by means of the anchor screw 24.

The cylinder Si is a double acting cylinder and supplies the power andmotion required for mov ing the slide ll toward and away from thestationary die mount I: and for causing the male die It to cooperatewith the stationary female die I: for performing the desired workclamping and forming operation. Oil or other suitable liquid underpressure is supplied to the cylinder 3| by means of a suitable pump lldriven by an electric motor 24. A reservoir 31 containinga supply ofsuch liquid is located in the hollow frame II of the machine and in thisinstance the pump 36 is located in an opening of the wall of thereservoir as shown in Fig. 3.

In a machine of this kind very heavy pressures are exerted by the maledie It against the work piece and the female die It. It is important tothe accuracy of the operations being performed that the female die It besecurely held against longitudinal shifting by such pressure and alsothat movement of the female die as the result of deflection in the diemount l2 or in the frame ll be minimized or substantially prevented.Such shifting or deflection can be. substantially prevented as far asthe female die i2 and its associated portion of the frame ii areconcerned, by providing a backing member or thrust block 39 on the frameand located at the rear of the die mount II, that is to say. on the sidethereof opposite the guideway l4.

The thrust block 48 can be formed as an integral part of the frame II,or preferably as here shown. is a rigid structure attached to the frameand which reinforces the latter. This thrust block has a base portionIla securely attached to the top of the frame i I and an uprightlongitudinal portion lib. The inner end of the upright portion llb is inthe form of an upright hollow post or section c which is engaged by thedie mount i2 and has a vertical height above the frame I i equal to ornearly equal to the height of the die mount. The thrust block SIprovides the frame II with a rigid thrust absorbing and reinforcingmember which backs up the die mount i2 and prevents or minimizesshifting or deflection of the die mount which might result in inaccuracyin the work or in an imperfect performance of the machine. The uprightsection 390 of the thrust block 29 also serves as a means for mountingan upright post or column 40 which forms a part of an overhead crane orwork handling device (not shown).

In the present machine It the pivotally mounted wings 2! which carry andmanipulate the bending dies 24 are actuated by individual powercylinders 42. These power cylinders are double acting hydrauliccylinders to which liquid under pressure can be supplied from the pump35 through the flexible conduits 25a. The cylinders 42 are disposed in arelatively inclined or divergent relation as shown in Figs. 1 and 2 withtheir outer or adjacent ends pivotally mounted on the outer end of thethrust block 38. These outer ends of the cylinders 42 are preferably notattached directly to the thrust block 39 but are attached to anchormembers 43 by means of the yokes and pivot pins 44 and 45 and themembers 48 are, in turn, adjustably connected with the outer end of thethrust block 39.

The cylinders 42 have reciprocable pistons therein and piston rods 46connected with such pistons project from the cylinders and have theirouter ends pivotally attached to the wings 25 by means of the yokes 41and pivot pins 48. By controlling the supply of liquid under pressure tothe cylinders 42 and the discharge of liquid therefrom the wings 25 canbe swung about their pivot axes 24 to thereby cause the bending dies 24to rock about the anvil portions "a of the male die I I and bend thework piece around the latter.

Since the cylinders 42 are pivotally mounted and are able to swing abouttheir pivotal connections 44 during the swinging of the wings 25, itwill be seen that these cylinders will act more directly and effectivelyto produce the desired swinging of the wings than if the actuation ofthe wings were accomplished through a linkage such as that shown in saidearlier patent. It will be seen also that the use of these pivotedindividual cylinders for actuating the wings and bending dies permitsthe machine to be considerably shortened in length and otherwiserendered more compact and satisfactory.

As already explained above the male die l can be used in cooperationwith the female die l3 so as to accomplish a forming operation on thework piece or for clamping the work piece when the latter is to be alsosubjected to a bending operation by the bending dies 24. When the die I5is used for forming operations only it is usually not necessary to swingthe carriage |'I because this kind of operation can ordinarily becarried out by a relative rapid closing and opening of the main dies l5and I3 by reciprocating the slide l5. In view of the heavy pressureswhich are applied to the work by the male die l5 and the fact that thedie I5 is located some distance above the guideway l4, it is importantto prevent the actuating thrust for the die I5 from being transmittedthrough the pivot post l8.

This can be accomplished for both simple stamping operations and bendingoperations of the machine by providing a holding means for the carriagell, preferably in the form of cooperating thrust elements 50, 5| and 52located at the outer or rear end of the carriage. The thrust element 55is a flange or projection provided on the carriage l1 and the elements5| and 52 are bars or abutment members extending transversely of theslide I5 and attached thereto by means of the clamping screws 5|a and52a. As shown in Fig. 4 the cooperating faces of the elements 50 and 5|are curved faces 53 and 54 whose center of curvature lies on the axis ofthe pivot' post l8. These cooperating curved faces 53 and 54 of theelements 55 and 5| are p'referably beveled as well as curved, as shownin the drawings, so that when the element 5| is drawn down by theclamping screws 5|a a wedging action can be obtained which will providefor some adjustment of the element 5| and will cause a tight engagementbetween the three thrust elements 50, 5I' and 52.

When the male die I 5 is to be used for the above mentioned simpleforming or stamping operations and is merely reciprocated by the .45

slide l5, the thrust element 5| is usually drawn down tightly by thescrews 5|a so that the thrust or reaction from the engagement of themale die l5 with the work and the female die l3 will be transmitteddirectly to the slide through the thrust elements 50, 5| and 52 anddeflection of the pivot post H3 or shifting of the carriage relativethat the desired swinging of the carriage can take place without unduebinding by the curved faces 53 and 54 of the thrust elements 55 and 5|.

During this swinging of the carriage I! the curved face 53 of the thrustelement 5|] slides relative to the curved face 54 of the stationarythrust element 5|. The radius of curvature provided for the faces 53 and54 permits the carriage IT to swing to its work-discharging position andto be returned to its working position and when the carriage has beenthus returned the thrust elements 50 and 5| will be in cooperatingengagement to receive the thrust when the main dies l5 and I3 are againclosed by forward movement of the slide l5. It will be understood ofcourse, that the clamping screws Blo are loosened only enough to permitthe desired relative sliding between the curved faces 53 and 54 which isnecessary to accommodate the swinging of the carriage. In other words,the thrust element 5| is always maintained in a position to effectivelyabsorb the thrust and prevent deflection of the pivot post l5,

Another important feature of the present machine'is the provision ofhold-down means for the carriage I1 and for the slide |5 so as toprevent a relative lifting of the male die l6 as the result of the heavythrust applied thereto when the dies are being closed. The hold-downmeans for the carriage l1 comprises cooperating elements 55 and 5'!provided respectively on the carriage and slide, and the hold-down meansfor the slide 5 comprises cooperating elements 58 and 59 providedrespectively on the frame and slide. The hold-down element 51 is in theform of a bar or flange on the forward or inner end of the slide l5 andthe hold-down element 55 comprises a lug or hook member mounted on thecarriage I1 and engaging .under the element 51 so as to prevent liftingor separation of the carriage relative to the slide. The cooperation ofthe elements 55 and 51 is such as to permit the carriage to be swung toits work discharging position and such that the element 55 will alwaysre-engage under the element 51 when the carriage is returned to itsworking position as shown in the drawings.

The hold-down means for the slide l5 becomes effective only during thefinal closing movement of the male die l5 at which time the forwardlyprojecting element 59 of the slide engages in a recess 58a located underor in the hold-down element 55 of the frame. When the element 59 engagesiii the recess 55a it effectively prevents lifting or separation of theslide |5 relative to the frame and resists or prevents relative liftingof the male die l5 which might otherwise occur as the result ofdeflection or accumulated lost motion between the various parts of themachine.

In the embodiment of the machine here shown the carriage I1 is providedwith an ejector cylinder 5| to which liquid can be supplied from thepump 35 for actuatin an ejector or kicker 52. The ejector 52 engages theendsof the bent work piece to discharge the same from the male die |5when the carriage H has been swung to its work-discharging position.

From the foregoing description and the accompanying drawings, it willnow be readily understood that the present invention provides animproved forming and bending machine in which metal work pieces can besubjected to forming and/or bending operations in a more satisfactorymanner than has heretofore been possible.

While the improved metal working machine of the present invention hasbeen illustrated and described herein in considerable detail, it will beunderstood, of course, that the invention is intended to include allchanges and modifications coming within the spirit of the invention andthe scope of the claims hereof. I

Having thus described my invention, I claim:

1. In a metal working machine of the character described, a frame havinga fixed die mount thereon, a stationary die on said mount, a slidemovable on said frame toward and away from said mount, a carriage, pivotmeans extending in projecting relation to the slide and mounting saidcarriage on said slide for swinging relative thereto, a die on saidcarriage and movable therewith for cooperation with said stationary diein subjecting a work piece to clamping and forming pressuretherebetween, means for reciprocating said slide for causing closing andopening of the dies and the application of said pressure to the workpiece, and cooperating thrust elements on said slide and carriage andlocated to receive the major portion of the working thrust during theclosing of the dies and prevent such thrust from being applied to saidpivot means.

2. In a metal bending machine of the character described, ai'rame havinga fixed die mount thereon, a stationary female die on said mount, aslide movable on said frame toward and away from said mount, a carriage,pivot means ex tending in projecting relation to the slide and mountingsaid carriage on said slide for swinging relative thereto, a male die onsaid carriage for cooperation with said stationary die in subjecting awork piece to clamping and forming pressure therebetween. means forreciprocating said slide for causing closing and opening of the dies andthe application of said pressure to the work piece, said male die havingcurved anvil portions thereon, bending die means adapted for rockingcooperation with said anvil portions for bending portions of the workpiece therearound while said pressure is being maintained, means foractuating said bending die means, and cooperating thrust elements onsaid slide and carriage and located to receive the major portion of theworking thrust during the closing of the dies and prevent such thrustfrom being applied to said pivot means.

3. In a metal bending machine of the character described, a frame havinga die mount fixed thereon, a stationary female die on said mount, aslide movable on said frame toward and away from said mount, a carriage,pivot means extending in projecting relation to the slide and mountingsaid carriage on said slide for swinging relative thereto, a male die onsaid carriage and movable therewith for cooperation with said stationarydie in subjecting a work piece to clamping and forming pressuretherebetween, means for reciprocating said slide for causing closing andopening of the dies and the application of said pressure to the workpiece, said male die having curved anvil portions thereon, bending diemeans adapted for rocking cooperation with said anvil portions forbending portions of the work piece therearound while said pressure isbeing maintained, means for actuating said bending die means, andcooperating relatively fixed and movable thrust elements on said slideand carriage and having cooperating thrust faces which are curved to aradius which permits swinging of said carriage on said pivot means.

4. In a metal bending machine of the character described, a frame havinga die mount fixed thereon, a stationary female die on said mount. aslide movable on said frame toward and away from said mount, a carriage,a male die on said carriage and movable therewith and having aclampingportion for cooperation with the stationary die in applyingclamping pressure to an intermediate portion of an elongated work pieceso that end portions of the work piece project outwardly from theclamped portion, said male die having anvil portions on opposite sidesof said clamping portion, bending die means adapted to cooperate withsaid anvil portions for bending the projecting portions of the workpiece therearound, means for actuating said bending die means, pivotmeans projecting from said slide and mounting said carriage on saidslide for swinging relative thereto from a working position insubstantial alignment with the path of movement of the slide to awork-dischargin DO- sition in angular relation to said path of movement.power means for reciprocating said slide, and hold-down means for saidcarriage adapted to become effective when said carriage is swung to saidworking position.

5. In a metal bending machine of the character described, a frame havinga die mount fixed thereon, a stationary female die on said mount, aslide movable on said frame toward and away from said mount, a carriage,a male die on said carriage and movable therewith and having a clampingportion for cooperation with the stationary die in applying clampingpressure to an intermediate portion of an elongated work piece so thatend portions of the work piece project outwardly from the clampedportion, said male die having anvil portions on opposite sides of saidclamping portion, bending die means adapted to cooperate with said anvilportions for bending the projecting portions of the work piecetherearound, means for actuating said bending die means, pivot meansprojecting from said slide .and mounting said carriage on said slide forswinging relative thereto from a working position in substantialalignment with the path of movement of the slide to a work-dischargingposition in angular relation to said path of movement, power means forreciprocating said slide, and hold-down means for said carriagecomprising a holding portion on said slide and means on the carriageengageable under said holding portion when said carriage is swung tosaid working position, said hold-down means being effective forsubstantially preventing relative lifting of the carriage during thecooperation of said dies.

6. In a metal bending machine of the character described, an elongatedhorizontally extending rigid frame having a die mount fixed thereon, astationary female die on said mount, a slide movable on said frametoward and away from said mount. acarriage, a male die on said carriageand movable therewith and having a clamping portion for cooperation withthe stationary die in applying clamping pressure to an intermediateportion of an elongated work piece so that end portions of the workpiece project outwardly from the clamped portion, said male die havinganvil portions on opposite sides of said clamping portion, bending diemeans adapted to cooperate with said anvil portions for bending theprojecting portions of the work piece therearound, means for actuatingsaid bending die means, pivot means projecting from said slide andmounting said carriage on saidslide for swinging relative thereto from aworking positionfin substantial alignment with the path of movement ofthe slide to a work-discharging position in angula'rrelation to saidpath of movemetng hold-down means for said slide adapted to omeeffective on the end of the slide nearest said die mount during thefinal portion of the relative closing movement of the die forsubstantially preventing lifting of the slide relative to the frame, andother hold-down means adapted to become effective when said carriage isswung to said working position for preventing lifting of the carriagerelative to said slide.

7. In metal bending apparatus of the character described, a frame havinga die mount fixed thereon, a stationary die on said mount, a slidereciprocable on said frame for movement toward and from said mount, amovable die carried by said slide for cooperation with said stationarydie in clamping an intermediate portion of a work piece therebetween sothat other portions of the work piece project outwardly from the clampedportion, said movable die having curved anvil portions at the sidesthereof, a pair of bending dies for bending portions of the work piecearound said anvil portions, a pair of pivotally mounted members locatedon opposite sides of said die mount and adapted to apply pressure tosaid bending dies and cause rocking of the latter relative to said anvilportions during the bending operation, means for reciprocating saidslide, and a pair of pivoted power cylinders having their outer endsoperatively connected with said frame rearwardly of said die mount andtheir inner ends connected with. said pivotally mounted members foractuating the same, said power cylinders extending in diverging relationso that their inner ends straddle said die mount.

8. In metal working apparatus of the character described, an elongatedsubstantially horizontal frame having a die mount thereon at anintermediate point and extending thereabove, a stationary die on saidmount, means extending along the frame and providing a guideway thereonon one side of said mount, a slide reciprocable on said guideway formovement toward and away from said mount, a movable die carried by saidslide for cooperation with said stationary die in clamping a work piecetherebetween, means for reciprocating said slide, said movable diehaving curved anvil portions at the sides thereof, a pair of bendingdies for bending portions of the work piece around said anvil portions,a pair of pivotally mounted members adapted to apply pressure to saidbending dies and cause rocking of the latter relative to said anvilportions during the bending operation, means on said frame andprojecting thereabove and forming a thrust block engaged by said diemount and extending along the frame and awayv from the die mount on theside of the latter opposite to said guideway, and a pair of powercylinders having pivotal connection with said thrust block and saidpivotally mounted members for imparting swinging movement to the latter.

9. In a metal working machine of the character described, an elongatedframe having a first die mount fixed thereon and laterally elongatedguide means extending away from said die mount, a slide movable on theguide means of said frame toward and away from said die mount, acarriage pivoted on said slide and having a second die mount locatedthereon at a point spaced above said guide means, a first die membercarried by the first die mount and spaced above said guide means, asecond die member carried by said second die mount and adapted forclosing cooperation with the first die member in applying pressure to awork piece received therebetween, said second die member having anvilportions thereon at the sides thereof, pivotally mounted bending diemembers adapted to cooperate with said anvil portions for bendingportions of the work piece therearound,

power means for actuating said slide to cause 10 relative closing andopening of said first and second die members, power means for actuatingsaid bending die members, and hold-down means for said slide located inthe space between said guide means and die mounts and adapted to be comeefl'ective on the end of the slide nearest said first die mount duringthe final portion of the relative closing movement of said first andsecond die members.

10. A metal working machine as defined in claim 9 in which saidhold-down means comprises recessed stationary means on said frameadjacent said first die mount and a projection on said slide engageablein said recessed means.

11. In a metal bending machine of the character described, an elongatedsubstantially horizontal frame having a die mount fixed thereon andextending thereabove, means on said frame providing a guideway extendingtherealong, a stationary die member carried by said mount and locatedabove the level of said guideway, a slide reciprocable on said guidewayfor movement toward and from said mount, a movable die member carried bysaid slide in upwardly ofl'set relation to said guideway and having aclamping portion for cooperation with the stationary die member inapplying clamping pressure to an intermediate portion of an elongatedwork piece so that end portions of the work piece project outwardly fromthe clamped portion, said movable die member having anvil portions onopposite sides of said clamping portion, bending die members adapted tocooperate with said anvil portions for bending the projecting portionsof the work piece therearound, power means for reciprocating said slide,fixed means on said frame and extending upwardly therefrom and forming athrust block engaged by said die mount and located on the side of thedie mount opposite to said guideway, said thrust block having arelatively high portion adjacent said die mount and a relatively lowportion more remote from said die mount, and a pair of divergent powercylinders for actuating said bending die members, said cylinders havingtheir widely spaced ends straddling the relatively high portion of saidthrust block and operably connected with said bending die members andtheir closely spaced ends extending over and operably connected withsaid relatively low portion of said thrust block.

LEE B. GREEN.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Honegger June 26, 1945

